This invention relates to electronically controlled sewing machines and, more particularly, to the storage of pattern data in such a sewing machine.
In recent years, electronically controlled sewing machines have become increasingly more sophisticated, with the designer's imagination being virtually the only limitation on the type of pattern which can be sewn. However, one hardware limitation is the size of the memory available for storing pattern data. This becomes a serious problem in the case of embroidery patterns, or monograms, wherein a single pattern consists of a great number of densely packed stitches--some embroidery patterns containing several hundred stitches. If the data for each and every stitch were to be stored in the memory, the sewing machine would require an unreasonably large amount of memory space in order to store more than just a few of these patterns.
It is therefore a primary object of this invention to provide a more efficient way of storing pattern data.
Many monogram patterns may be considered to involve satin stitching over a continuous path. If this path could be expressed in terms of mathematical equations and if these equations were stored in the memory then it would be possible to reduce the amount of storage required for the pattern.
It is therefore another object of this invention to store pattern information in the form of mathematical equations defining the pattern.
However, to recreate the mathematical equations from stored information and to then derive signals for controlling the stitch forming instrumentalities involves very complex and time consuming computations which are not practical.
It is therefore a further object of this invention to provide the means whereby only simple computations are required to recreate a stitch pattern from stored information representing the pattern expressed in terms of mathematical equations.